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y 3, 1955 K. HENRICHSEN Re. 23,993

PUHP Original Filed law 22, 1947 4 Sheets-Sheet 3 INVBV TOR. K/Vl/Tl/[NK/Cl/SEN BY M ITTOANEY My 3, 1955 HENRICHSEN PUMP 4 Sheets-Sheet 4Original Filed May 22, 194'? INVENTOR.

KNUT HEhRlCHSEN gToRNEY United States Patent Ofi ice Re. 23,993 ReissuedMay 3, 1955 Knut Henrichsen, Los Angeles, Calif., lssignor to NorthAmerican Aviation, Inc.

Original No. 2,604,856, dated July 29, 1952, Serial No.

749,629, May 22, 1947. Application for reissue De cember 18, 1953,Serial No. 399,184

4 Claims. (Cl. 103-162) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted ln italics indicates the additions made by reissue.

This invention relates to a transmission of a hydrostatic generator (orpump) and motor type comprising new and novel features of construction.

It is an object of this invention to provide a variable speedtransmission composed essentially of an engine driven generator or pumpof variable stroke and a motor of constant stroke.

It is a further object of this invention to provide a light weightcompact transmission capable of operating at a relatively high R. P. M.such as may be encountered in connection with modern automotive engines.

It is a further object of this invention to adapt a swash-plate type ofpump for use in such a transmission. It is still a further object ofthis invention to provide a transmission which operates at a relativelyhigh fluid pressure.

It is yet another object of this invention to provide a swash-plate typeof pump with a fluid bearing arrangement for carrying end thrust so asto avoid the use of excessively large antifriction bearings.

It is yet another object of this invention to provide a swash-plate typeof pump with a fluid bearing arrangement for carrying end thrust so asto avoid excessively high friction at low R. P. M.

It is still another object of this invention to provide a cylindergrouping in a conical arrangement to obtain compactness and reduce fluidturbulence losses, as well as to reduce valve face friction losses.

It is yet another object of this invention to provide a pump valvearrangement having a spherical valve face thus to obtain self-aligningwith an associated cylinder block face and a reduction of radial load onthe centering bearing for the cylinder block.

It is still another object of this invention to provide a light weighttransmission which will efficiently function in connection with modernautomotive engines.

Other objects of invention will become apparent from the followingdescription and the drawings, in which Fig. l is a sectional view, withparts in elevation showing the invention;

Fig. 2 is an enlarged sectional view of one of the fluid bearingelements;

Fig. 3 is a sectional view, with parts in elevation, of a pistonarrangement forming a part of the invention; Fig. 4 is a sectional view,with parts in elevation, of a fixed block containing a valve arrangementand providing spherical bearing surfaces for cylinders of the generatorand motor units;

Fig. 5 is a view taken along the line 5--5 of Fig. 4; Fig. 6 is a viewtaken along the line 6-6 of Fig. 1; Fig. 7 is a view taken along theline 7-7 of Fig. 1; Fig. 8 is a detail view showing means for adjustingthe thrust block and bearing unit for controlling the pump stroke; [and]Fig. 9 is a detail view of a shuttle valve[.]; and Fig. 10 is anenlarged sectional view illustrating the concentric curvature of thethrust block and valve plate, and the fluid bearing means for thecylinder block and valve plate.

Referring to the drawings there is shown in Fig. 1 a generator unit A, amotor unit B, and connections whereby the motor unit is driven by thegenerator unit. Generally speaking, the generator unit is adapted to beconnected by means of shaft 1 to a source of power such as an automotiveengine, while the motor unit is adapted to be connected by shaft 2 to atorque tube or drive shaft of an automobile or the like. Shafts l and 2are drivingly connected by the hydrodynamic transmission constitutingthe present invention.

In general, the transmission is constructed as follows: Shaft 1 isrotatably supported in end plate 4 of housing 3 by antifriction bearing5 and is operatively connected to a hollow shaft 7 by a constant-speeduniversal joint 6. Such joint is well known in the art and is sometimesreferred to as a constant velocity universal joint by reason of the factthat shafts angularly positioned with respect to each other andconnected thereby can be made to rotate at equal angular velocitiesirrespective of the angle at which the shafts are placed with respect toeach other. Hollow shaft 7 is rotatably supported by bearings 8 andthrust block 9 which in turn is adjustably mounted in housing 3 (seeFig. 8) by trunnions 10 and gear 11 adapted to be connected to a handcrank or an automatic control mechanism or the like (not shown). Hollowshaft 7 is provided with portions 12 for receiving bearing elements 13fioatingly carried by end portions 14 of connecting rods 15. Bearingelements 13 (substantially hemispherical in form) are provided with aspherical bearing face 16 adapted to cooperate with a correspondingspherical bearing surface 17 on block 9. The end portions 14 areoperatively positioned by members 18 of suitable shape which are held inposition by suitable member 19 (see Figs. l and 7) fastened to hollowshaft 7 by means of pins 20. Connecting rods 15 are each provided with apiston 21 slidably received in cylinders 22 of a cylinder block 23 whichin turn is rotatably supported by an antifriction bearing 24 on a shaft25 supported in turn by being screw-threaded into valve block 26 (seeFig. 4). Shaft 25 is adapted to carry a spring (not shown) identicalwith spring 50a and adapted to hold the inner bearing race of bearing 24in place in the same manner that spring 50a holds inner bearing race ofbearing 24a in place. Shaft 25a is provided with a suitable split ringor the like adapted to engage the other end of spring 50a. Spring 50a,interposed between the split ring and the inner race of bearings 24a,can be seen in Fig. I. Springs 30 and 30a bear at one of their endsagainst the outer races of bearings 24 and 24a, respectively. The otherends of these springs bear respectively, against shafts 27 and 27a.Cylinder block 23 is drivingly connected to shaft 1 by means of shaft 27having a spline or other suitable connection (with some tolerance) withshaft 1 to be driven thereby. Shaft 27 is provided with cars 28 forengaging corresponding recesses 29 in cylinder block 23. Spring 30,placed between cylinder block 23 and shalt 27, operatively positionsthese parts and at the same time permits a slight amount of movement inrespect thereof to permit alignment of cylinder block 23 with itsbearing surface 32. it may be noted that the axes of cylinders 22 areangularly arranged to converge at a common point. Accordingly, thecorresponding spherical faces 31 and 32 of cylinder block 23 and valveblock 26 respectively are made concentric about such point. Similarly.surfaces 16 and 17 on elements 13 the generator piston stroke is zero.

spherical surfaces on motor parts 13a and 34 are made to the same radiusas surfaces 16 and 17 'on the generator. The conical arrangement of thecylinders along with the spherical surfaces on valve block 26 and parts13, 13a and thrust blocks 9 and 34, reduce the load on bearings such as8, 8a, 24, and 24a.

In the preferred embodiment of the invention generator and motor unitsare attached to the valve block 26 by a bolt or other suitable means 33although it is to be understood that the generator and motor units maybe separated if desired and driving fluid from the generator unit Aconducted, in any suitable manner by tubes or the like, to motor unit B.The valve block or its equivalent may be suitably divided or split andthe parts suitably connected by piping. Of course, generator unit A maybe used alone wherever a source of pressurized fluid is needed.

The motor unit is similar to the generator unit in all respects exceptfor details which will be hereinafter specifically pointed out.Otherwise, parts carrying the suffix "a" correspond to the samereference numeral in respect of generator A. The only substantialdifference between the generator and motor units comprises the thrustblocks 9 and 34, block 9 of which is adjustable as previously described,and block 34 of which is suitably fixed to the casing 3a and end plate4a. Accordingly, hollow shaft 7a is fixed to or integral with shaft 2 torotate therewith, and constant speed universal joint 35 serves totransmit torque from shaft 27a to hollow shaft 7a and shaft 2, shafts27a and 2 remaining at a predetermined angle with respect to each other.

Referring now to Figs. 4 and 5 taken in connection with Fig. l, valveblock 26 is provided with a pair-of ports 36 and 37. Fluid is suppliedto these ports by means of shuttle valve 38 and passageways 39 and 40interconnecting the shuttle valve with the ports 36 and 37. Shuttlevalve 38 is of a type well known in the art and comprises two headportions 51 and '52 having valve faces 53 and 54 adapted to cooperatewith corresponding faces in valve block 26. A stem portion is providedwith spaced projecting portions such as 56 to provide a suitable bearingfor the valve while at the same time permitting the flow of oil alongthe stem from the passageway 41 to either of the ports 39 or 40. Fluidunder pressure is supplied to the shuttle valve through passageway 41connected by a pipe or tube (not shown) to port 42 (Fig. 1) throughwhich oil is expelled under pressure as a result of action of impeller43 suitably attached to shaft 1. The shuttle valve seats alternativelyagainst corresponding faces in block 26, depending upon difference inpressure between ports 36 and 37. Operation of the shuttle valveprovides oil from port 42 to the low pressure side of the system for thepurpose of replacing fluid which leaks from the high pressure side intothe casing. The low pressure side may be connected through either ofports 39 or 40 depending upon the angle of the swash-plate and whetherthe motor is driving or being driven by the generator.

The fluid bearing constituting a part of the invention has threeapplications in the present disclosure. These are the valve blockfacings 32, the connecting rod flange 14, and the half-ball face 16.Taking the latter application as a typical example, it is seen that thebearing under the. dam is slightly less than the resultant of the pistonload along the centerline of the half-ball 13. The load not carriedwithin the outside diameter of the dam is carried on the fluid filmbetween the halfball and the bearing block in the contact area betweenthe outside of groove 47 and the outside edge of the ball. The upperpart of half-ball 13 is provided with a fluid bearing and darnarrangement similar to that shown on the lower part of the half-ball.Thus, portion 50 corresponds to 46, and groove 51 and duct 52correspond, respectively, to groove 47 and duct 48. Face 31 is providedwith a groove 53 and duct 54 similar to groove 47 and duct .48.

In the operation of the device, rotation of the shaft 1, correspondingto rotationof the drive shaft of an engine to which it is connected,will in turn cause operation of the generator unit A to displace fluidin accordance with the adjustment of thrust block 9. The fluid sodisplaced will in turn result in operation of the motor unit B, byreason of fluid flow through ports 36 and 37, to operate shaft' 2.Direction and amount of oil flow is dependent upon adjustment of block9.

The arrangement comprising the present invention has many advantagesover prior constructions. Among these are: the arrangement wherein endthrust of the cylinders and cylinder block arrangements is mrried byfluid bearing means-the cylinder block being provided with a sphericalsurface adapted to bear upon a. corresponding surface upon the valveblock; the centerline of the cluster of cylinders intersect at a pointwhich serves as a radius for the bearing surface between the cylinderblock and the valve block as well as between the thrust block and theindividual thrust bearing elements on the connecting rod; the placing ofthe cylinders on an angle provides a reduced travel for the frictionload between the cylinder block and the valve face, as well as improvingthe hydraulic radius of the passages for hydraulic flow between thegenerator and motor units; the spherical bearing surfaces also providethat the thrust loads are normal to the bearing surfaces, therebyreducing or avoiding radial loads on the antifn'ction type centeringbearings; the members 13 in Fig. 2 beingcurved to correspond to bearingface 17 of member 9, and being substantially freely floating, reduce thenecessity for accurate machining of the larger surface since thecorresponding bearing surfaces will satisfactorily adjust themselveswithout undue leakage under the dam portion of part 13; the provision ofshaft 27 in Fig. 1 enables block 23 to satisfactorily align itself withrespect to its bearing surface.-

face comprises a cup-shaped center portion 46 connected to the cylinderby ducts 44 and 45. The pressure in this cup-shaped portion issubstantially the same as in the cylinder. Since groove 47 is connectedby ducts 48 and 49 to the interior of the casing, the pressure in thegroove is the same as in the casing. The surface of the ball betweenspace 46 and the outside diameter of groove 47 constitutes a dam inrespect of which fluid pressure drops from cylinder pressure to casingpressure according to the physical laws of flow of viscous fluid incapillary spaces. The dam is proportioned in such a manner that theresultant of the pressure inside and Although the invention has beendescribed and illustrated in detail, it is to be clearly understood thatthe same is by way of illustration and example only, and is not to betaken by way of limitation, the spirit and scope of this invention beinglimited only by the terms of the appended claims.

I claim:

1. [In a hydraulic transmission] A pump comprising a cluster ofcylinders forming a cylinder block, pistons [and connecting rods]operatively associated with said cylinders, inlet and outlet portsoperatively associated with said cylinders, means for driving saidpistons with respect to said cylinders, said means includingcomplementary bearing surfaces and means to inject fluid therebetween toprovide a fluid bearing means for absorbing the thrust load 0 saidpistons, and complementary bearing surfaces and means to inject fluidtherebetween to provide a fluid bearingmaiistor absorbing the axialthrust load of said cylinder bltlck, said driving means being adjustableto vary the stroke of said piston: from and to a condition of zerostroke, [and fluid bearing means for absorbing the thrust load of saidconnecting rods,] the centerlines of said cylinders being inclined toconverge at a. common point, and [the] said complementary surfaces ofsaid two fluid bearing means being concentric with such point in acondition of zero stroke of said pump.

2. [In a hydraulic transmission] A pump comprising open-ended cylindersforming a cylinder block, said cylinder block including a bearingsurface, [pistons] a piston and connecting rod received in each of saidcylinders through one 01 the open ends thereof, a valve block engaged bysaid bearing surface of said cylinder block and having ports coordinatedwith the other open ends of said cylinders for passage of fluidthercthrough, means for driving said pistons with respect to saidcylinders, connecting rod bearings attached to saidconnecting rods, anda thrust block adapted to be engaged by said connecting rod bearings;said thrust block being movable for varying the stroke of said piston:from and to a neutral position of zero stroke, said connecting rodbearings comprising hemispherical members fioatingly carried by saidconnecting rods for engagement by said thrust block, and passagewaysthrough said [cylindem] pistons, connecting rods, and bearing members,arranged to permit passage'of fluid from said cylinders to said bearingsurfaces whereby to oppose the thrust loads of said cylinder block andconnecting rod bearing members, the centerlines of said cylinders beinginclined to converge at a common point, and the bearing surface of saidcylinder block and of said thrust block when in said neutral positionbeing concentrically curved about such common point.

3. A pump comprising a cluster of cylinder: forming a cylinder block, apiston and connecting rod means operatively associated with each of saidcylinders, said means including bearing surfaces, valve block meansincluding inlet and outlet port: operatively associated with saidcylinders, said valve block means and said cylinder block havingcooperating complementary bearing surfaces, means for rotating saidcylinder block, a thrust block having a bearing surface adapted to beengaged by a portion of said piston and connecting rod means bearingsurfaces, said thrust block being movable to an mgle relative to saidcylinder block whereby said piston and connecting rod means are drivenwith respect to said cylinder: upon rotation of said cylinder block, thecenterlines of said cylinder: being inclined to converge at a commonpoint, the bearing surface of Ilaid cylinder block, valve block andthrust block being concentrically curved aboutruch mnunan point.

4. A pump comprising a cluster of cylinders forming a cylinder blocx,said cylinder block having a bearing surface, a piston and rod meansoperatively associated with each of said cylinders, said rod meansincluding a bearing surface, means for rotating said cylinder block,valve means, said valve means including a surface cornplementary to saidcylinder block bearing surface and communicating with said cylinder: toobtain fluid un der pressure therefrom to provide a fluid bearing meansfor absorbing the axial thrust load of said cylinder block, said valvemeans further including inlet and outlet ports therein operativelyassociated with said cylinders, and a thrust block including a bearingsurface, said thrust block bearing surface being complementary to saidrod means bearing surface, said piston and rod means including mean: forinjecting fluid under pressure from said cylinders between said rodmeans bearing surface and said thrust block bearing surface to provide afluid bearing means for absorbing the thrust load of said piston and rodmeans, said thrust block being angularly adjustable with respect to saidcylinder block whereby rotation of said cylinder block driver saidpiston and rod means with respect to said cylinders, the centerline: ofsaid cylinders being inclined to converge at a common point, and saidbearing surfaces being concentric with such point in a condition of zerostroke of said pump.

References Cited in the tile of this patent or the original patentUNITED STATES PATENTS Re. 20,0216 Thoma June 30, 1936 1,152,729Hale-Shaw Sept. 7, 1915 1,263,180 Williams Apr. 16, 1918 1,274,391 DavisAug. 6, 1918 1,308,844 Ferris at al July 8, 1919 1,840,872 Rayburn Ian.12, 1932 1,996,994 Grubb Apr. 9, 1935 2,043,111 Meyer June 2, 19362,241,701 D00 May 13, 1941 2,272,771 Hawley Feb. 10, 1942 2,292,125Ifield Aug. 4, 1942 2,296,929 meld Sept. 29, 1942 2,299,235 Snader Oct.20, 1942 2,371,974 Neuland Mar. 20, 1945 2,483,856 Temple Oct. 4, 1949

